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> Your IP address is a largely irrelevant metric in modern tracking systems.
I don't believe this for one second.
Your IP address on its own is not sufficient to identify you. That doesn't mean your IP address is not helpful in identifying you.
If you have Javascript disabled, it is a heck of a lot easier to identify you with a combination of an IP address, user agent, and OS than it is to identify you without the IP address cutting down the pool of potential visitors.
On top of that, if you're targeting me and do a geo-location of my IP address, it will get you within 5 miles of my house. That's close enough that you'll know which county I'm in, which with a few other easily-obtained pieces of information will let you pull up my voter registration, which will give you my exact street address.
Of course, you could mitigate this by setting up your own VPN on something like Linode, but unless you're regularly rotating IP addresses, you've just traded a pseudo-identifier that multiple people/devices share for a persistent identifier.
This argument comes up all the time, and I have never heard anyone explain it in a way that passes my sniff test. If you want me to stop using a VPN, you need to do a lot better than just claiming that IP addresses don't matter -- you need to show some kind of evidence to back that up.
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Broadcasting your IP address to every website you've ever visited is a completely valid concern that gets hand-waved out the wazoo whenever this subject comes up.
I've sent bug reports to sites that publicly tied IP addresses to comments/accounts so anyone could track your movement patterns over time. Yes, that info can be useful to an attacker trying to deanonomyze you. Yes, that info can be used to link users together. Yes, that info can be used to narrow the pool of potential visitors so other fingerprinting techniques are more powerful.
It is blanketly ridiculous to claim that an approximate county-level geolocation isn't a useful data-point to attackers. If IP addresses weren't useful, the Tor project wouldn't be going to such lengths to hide them.